Heat-transfer label assembly and method of using the same

ABSTRACT

A heat-transfer label assembly and method of using the same. In one embodiment, the assembly is adapted for decorating glass articles and comprises a carrier, the carrier comprising a paper substrate overcoated with a layer of polyethylene. The polyethylene layer is overcoated with a skim coat of wax. One or more heat-transfer labels are printed onto the skim coat and are spaced apart from one another. Each label consists of one or more ink design layers, each ink design layer comprising a binder resin, a pigment, a cross-linking resin and a catalyst. The catalyst is capable of causing the cross-linking resin to cross-link the binder resin within 1-2 minutes after the label has been transferred to a glass article that has been preheated to a temperature of about 250° F.-325 ° F.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit under 35 U.S.C. 119(e)of U.S. Provisional Patent Application Serial No. 60/349,134, filed Jan.16, 2002, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] The present invention relates generally to heat-transfer labelassemblies and more particularly to a novel heat-transfer label assemblyand to a method of using the same.

[0003] Heat-transfer labels are implements commonly used to decorateand/or to label commercial articles, such as, and without limitation to,containers for beverages (including alcoholic beverages, such as beer),essential oils, detergents, adverse chemicals, as well as health andbeauty aids. As can readily be appreciated, heat-transfer labels aredesirably resistant to abrasion and chemical effects in order to avoid aloss of label information and desirably possess good adhesion to thearticles to which they are affixed. Heat-transfer labels are typicallyconstructed as part of a heat-transfer label assembly, with one or moreheat-transfer labels printed on a removable carrier web.

[0004] One of the earliest types of heat-transfer label assemblies isdescribed in U.S. Pat. No. 3,616,015, inventor Kingston, which issuedOctober, 1971, and which is incorporated herein by reference. In theaforementioned patent, there is disclosed a heat-transfer label assemblyadapted for labeling plastic objects, the heat-transfer label assemblycomprising a paper sheet or web, a wax release layer affixed to thepaper sheet, and an ink design layer printed on the wax release layer.In the heat-transfer labeling process, the label-carrying web issubjected to heat, and the label is pressed onto a plastic article withthe ink design layer making direct contact with the plastic article. Asthe paper sheet is subjected to heat, the wax layer begins to melt. Thisenables the paper sheet to be released from the ink design layer, with aportion of the wax layer being transferred with the ink design layeronto the plastic article and with a portion of the wax layer remainingwith the paper sheet. After transfer of the design to the plasticarticle, the paper sheet is immediately removed, leaving the designfirmly affixed to the plastic article and the wax transferred therewithexposed to the environment. The wax layer is thus intended to serve twopurposes: (1) to provide release of the ink design from the web uponapplication of heat to the web and (2) to form a protective layer overthe transferred ink design. After transfer of the label to the article,the transferred wax release layer is typically subjected to apost-flaming or post-heating technique which involves subjecting thetransferred wax release layer to jets of high temperature gas either asdirect gas flames or as hot air jets to produce wax surface temperaturesof about 300° F. to 400° F. for a period of time sufficient to remeltthe transferred wax. This remelting of the transferred wax is performedto enhance the optical clarity of the wax protective layer (therebyenabling the ink design layer therebeneath to be better observed) and toenhance the protective properties of the transferred wax release.

[0005] Unfortunately, despite the aforementioned post-flaming step, thetransferred wax layer is often perceptible on clear and/or dark-coloredobjects.

[0006] Consequently, a great deal of effort has been expended inreplacing or obviating the need for a wax release layer. One type ofheat-transfer label assembly that does not include a wax release layeris exemplified by U.S. Pat. No. 4,935,300, inventors Parker et al.,which issued Jun. 19, 1990, and which is incorporated herein byreference. In the aforementioned Parker patent, the label assembly,which is said to be particularly well-suited for use on high densitypolyethylene, polypropylene, polystyrene, polyvinylchloride andpolyethylene terephthalate surfaces or containers, comprises a papercarrier web which is overcoated with a layer of thermoplasticpolyethylene. A protective lacquer layer comprising a polyester resinand a relatively small amount of a nondrying oil is printed onto thepolyethylene layer. An ink design layer comprising a resinous binderbase selected from the group consisting of polyvinylchloride, acrylics,polyamides and nitrocellulose is then printed onto the protectivelacquer layer. A heat-activatable adhesive layer comprising athermoplastic polyamide adhesive is then printed onto the ink designlayer.

[0007] Although the above-described Parker label assembly substantiallyreduces the wax-related effects discussed previously, said labelassembly does not quite possess the same release characteristics ofheat-transfer label assemblies containing a wax release layer. In fact,when put to commercial use, the polyethylene release layer of the Parkerlabel assembly was found to become adhesive when subjected to the typesof elevated temperatures typically encountered during label transfer.Accordingly, another type of heat-transfer label assembly differs fromthe Parker heat-transfer label assembly in that a very thin layer or“skim coat” of carnauba wax is interposed between the polyethylenerelease layer and the protective lacquer layer to improve the release ofthe protective lacquer from the polyethylene-coated carrier web. Thethickness of the skim coat corresponds to approximately 0.1-0.4 lbs. ofthe wax spread onto about 3000 square feet of the polyethylene releaselayer. The aforementioned “skim coat-containing” heat-transfer labelassembly also differs from the Parker label assembly in that theheat-activatable adhesive of the “skim coat” label assembly is printedover the entirety of the ink and protective lacquer layers, with theperipheral edges of the adhesive layer in direct contact with the waxskim coat.

[0008] An example of a “skim coat-containing” heat-transfer labelassembly of the type described above is disclosed in U.S. Pat. No.6,099,944, inventors Laprade et al., which issued Aug. 8, 2000, andwhich is incorporated herein by reference. According to theaforementioned patent, a label assembly is provided that is designed foruse in decorating clear glass articles in such a way as to give sucharticles the appearance of having been frosted. In a preferredembodiment, the label includes (a) a support portion in the form of asheet of paper overcoated with a release layer of polyethylene, (b) askim coat of wax overcoated onto the polyethylene release layer and (c)a transfer portion, the transfer portion including a protective lacquerlayer printed onto the skim coat, an ink layer printed onto theprotective lacquer layer, and an adhesive layer printed onto the inklayer, as well as onto any exposed portions of the underlying protectivelacquer layer and onto a surrounding area of the skim coat. Theprotective lacquer layer comprises a solvent-soluble phenoxy resin thathas been cross-linked by a melamine resin. The ink layer comprises adesign printed with a frosted ink, the frosted ink preferably comprisinga solvent-soluble phenoxy resin, a silica and a colorant. The adhesivelayer comprises a phenoxy resin of the type present in a water-basedphenoxy resin dispersion.

[0009] Examples of other “skim coat-containing” heat-transfer labelassemblies are disclosed in the following U.S. patents, all of which areincorporated herein by reference: U.S. Pat. No. 5,800,656, inventorsGeurtsen et al., issued Sep. 1, 1998; U.S. Pat. No. 6,096,408, inventorsLaprade et al., issued Aug. 1, 2000; U.S. Pat. No. 6,033,763, inventorsLaprade et al., issued Mar. 7, 2000; and U.S. Pat. No. 6,083,620,inventors Laprade et al., issued Jul. 4, 2000.

[0010] When using a “skim coat-containing” heat-transfer label assemblyof the type described above to decorate an article, one typicallypreheats the article and the label assembly prior to decoration. (Wherethe article is made of glass, the article is typically preheated to atemperature of about 300° F. In addition, a silane adhesion promoter isalso typically applied to the glass article prior to preheating.)Decoration is typically performed by applying heat to the bottom of thecarrier while the top of the label is pressed against the article. Oncethe transferred portion of the heat-transfer label assembly has beenapplied to the article, the labeled article is then typically subjectedto a post-heating step so that the protective lacquer layer and/or theadhesive layer, one or both of which typically comprise thermosettingresins, may be cured. (By contrast, the ink layer of the above-describedheat-transfer label assembly does not include a thermosetting resin.)Said post-heating step is typically performed by conveying the labeledarticles through one or more industrial ovens to heat the articles to anelevated temperature, such as 400° F., for a particular amount of time,typically 15-20 minutes. However, as can readily be appreciated,industrial ovens of the aforementioned type are not only space-consumingbut also very expensive to purchase, to maintain and to operate.

[0011] Accordingly, the present inventor has identified a need for aheat-transfer label assembly that does not require the post-heating ofthe labeled article.

SUMMARY OF THE INVENTION

[0012] It is an object of the present invention to provide a novelheat-transfer label assembly.

[0013] It is another object of the present invention to provide aheat-transfer label assembly as described above that overcomes at leastsome of the problems associated with existing heat-transfer labelassemblies of the type described above, such as the need for apost-heating step of the labeled article.

[0014] In furtherance of the above and other objects to be set forth orto become apparent from the description to follow, and according to oneaspect of the invention, there is provided a heat-transfer labelassembly, said heat-transfer label assembly comprising (a) a carrier;(b) a wax skim coat deposited onto said carrier; and (c) a heat-transferlabel, said heat-transfer label being deposited onto said wax skim coatfor transfer of said heat-transfer label from said carrier to an articleunder conditions of heat and pressure, said heat-transfer labelcomprising one or more ink design layers, each of said ink design layersbeing thermosetting within about 1-2 minutes after said ink design layerhas been transferred to an article heated to a temperature of about 250°F.-325° F.

[0015] Preferably, said carrier comprises a paper substrate overcoatedwith a layer of polyethylene, said wax skim coat being deposited ontosaid polyethylene layer. In addition, said heat-transfer labelpreferably consists of said one or more ink design layers, each of saidink design layers preferably comprising a binder, such as a polyesterresin, a colorant and a cross-linking system. Said cross-linking systempreferably comprises a cross-linking resin, such as amelamine-formaldehyde resin, and a heat-activatable catalyst, such as anamine-blocked sulfonic acid catalyst, for catalyzing the cross-linkingof said cross-linking resin to the binder within about 1-2 minutes aftertransfer of said heat-transfer label to an article heated to atemperature in the range of about 250° F.-325° F.

[0016] According to another aspect of the invention, there is provided aheat-transfer label assembly, said heat-transfer label assemblycomprising (a) a carrier; and (b) a heat-transfer label, saidheat-transfer label being deposited onto said carrier for transfer ofsaid heat-transfer label from said carrier to an article underconditions of heat and pressure, said heat-transfer label comprising oneor more ink design layers, each of said ink design layers beingthermosetting within about 1-2 minutes after said ink design layer hasbeen transferred to an article heated to a temperature of about 250°F.-325° F.; (c) wherein said carrier is made of a non-wax material thatseparates cleanly from said heat-transfer label with no visuallydiscernible portion of said carrier being transferred to the articlealong with said heat-transfer label. Preferably, said carrier comprisesa polymeric film overcoated with a release coating made of a non-wax,non-silicone, thermoset release material, said release coating having atotal surface energy of about 25 to 35 mN/m, of which about 0.1 to 4mN/m is polar surface energy, and having a carbon content (by atomic %)of about 97% and an oxygen content (by atomic %) of about 3%, asmeasured by X-ray photoelectron spectroscopy.

[0017] The present invention is also directed to an ink formulation,said ink formulation comprising (a) a binder resin; (b) a colorant; (c)one or more volatile solvents; and (d) a cross-linking system, saidcross-linking system being adapted to effect cross-linking of the binderresin within about 1-2 minutes after application of a dried, printeddesign made with said ink formulation to an article heated to atemperature of about 250° F.-325° F.

[0018] The present invention is further directed to a method ofdecorating a glass article, said method comprising the steps of (a)providing a heat-transfer label assembly, said heat-transfer labelassembly comprising (i) a carrier; and (ii) a heat-transfer label, saidheat-transfer label being releasably secured to said carrier fortransfer of said heat-transfer label from said carrier to a glassarticle under conditions of heat and pressure, said heat-transfer labelcomprising one or more ink design layers, each of said ink design layersbeing thermosetting within about 1-2 minutes after said ink design layerhas been transferred to a glass article heated to a temperature of about250° F.-325° F.; (b) providing a glass article; (c) heating said glassarticle to a temperature of about 250° F.-325° F.; and (d) while saidglass article is at said temperature of about 250° F.-325° F.,transferring said heat-transfer label from said carrier to said glassarticle.

[0019] For purposes of the present specification and claims, it is to beunderstood that certain terms used herein, such as “on” or “over,” whenused to denote the relative positions of two or more layers of aheat-transfer label, are primarily used to denote such relativepositions in the context of how those layers are situated prior totransfer of the transfer portion of the label to an article since, aftertransfer, the arrangement of layers is inverted as those layers whichwere furthest removed from the associated support sheet are now closestto the labelled article.

[0020] Additional objects, as well as features, advantages and aspectsof the present invention, will be set forth in part in the descriptionwhich follows, and in part will be obvious from the description or maybe learned by practice of the invention. In the description, referenceis made to the accompanying drawings which form a part thereof and inwhich is shown by way of illustration specific embodiments forpracticing the invention. These embodiments will be described insufficient detail to enable those skilled in the art to practice theinvention, and it is to be understood that other embodiments may beutilized and that structural changes may be made without departing fromthe scope of the invention. The following detailed description is,therefore, not to be taken in a limiting sense, and the scope of thepresent invention is best defined by the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which are hereby incorporated into andconstitute a part of this specification, illustrate preferredembodiments of the invention and, together with the description, serveto explain the principles of the invention. In the drawings wherein likereference numerals represent like parts:

[0022]FIG. 1 is a schematic section view of a first embodiment of aheat-transfer label assembly constructed according to the teachings ofthe present invention; and

[0023]FIG. 2 is a schematic section view of second embodiment of aheat-transfer label assembly constructed according to the teachings ofthe present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0024] Referring now to FIG. 1, there is shown a schematic section viewof a first embodiment of a heat-transfer label assembly, saidheat-transfer label assembly being represented generally by referencenumeral 11.

[0025] Assembly 11 comprises a carrier 13. Carrier 13, in turn,comprises a paper substrate 15 overcoated with a polyethylene layer 17.Details of polyethylene layer 17 are disclosed in U.S. Pat. Nos.4,935,300 and 4,927,709, the disclosures of which are incorporatedherein by reference.

[0026] Assembly 11 also comprises a wax skim coat 19 of the typedescribed above, skim coat 19 being coated directly on top of theentirety of polyethylene layer 17. As will be explained below in greaterdetail, during label transfer, a portion of skim coat 19 is typicallytransferred along with the label onto the article being decorated, and aportion of skim coat 19 remains on top of polyethylene layer 17.

[0027] Assembly 11 further comprises a plurality of spaced-apartheat-transfer labels 21-1 and 21-2 (it being understood that, althoughtwo heat-transfer labels 21 are shown in the present embodiment,assembly 11 could be modified to include any number of such labels),heat-transfer labels 21-1 and 21-2 being positioned directly on top ofskim coat 19 for transfer of labels 21-1 and 21-2, under appropriateconditions of heat and pressure, from carrier 13 to suitable articles,such as glass containers.

[0028] In the present embodiment, heat-transfer label 21 consists of oneor more ink design layers printed directly onto skim coat 19. Each ofsaid one or more ink design layers is formed by depositing, preferablyby gravure printing, an ink composition of the type to be describedbelow and, thereafter, allowing the volatile solvent(s) of the inkcomposition to evaporate, leaving only the non-volatile components ofsaid ink composition to form label 21.

[0029] The ink composition of the present invention comprises (i) aresinous binder; (ii) a cross-linking system adapted to effectcross-linking of the resinous binder within about 1-2 minutes aftertransfer of label 21 to an article that has been heated to a temperatureof about 250° F.-325° F., preferably about 275° F.-325° F.; (iii) acolorant; and (iv) one or more suitable volatile solvents.

[0030] Said resinous binder may be one or more resins of the typecommonly used in heat-transfer label inks including, but not limited to,polyester resins, polyester/vinyl resins, polyamide resins, phenoxyresins, epoxy resins, polyketone resins, and acrylic resins. Examples ofpreferred resins include ViTEL® 2700 (Shell Chemical Company, Akron,Ohio), a copolyester resin having a high tensile strength (7000 psi) anda low elongation (4% elongation), and ViTEL® 2300 (Shell ChemicalCompany), another copolyester resin having a high tensile strength (8000psi) and a low elongation (7% elongation).

[0031] A vinyl chloride/vinyl acetate resinous binder may be added tothe aforementioned binder(s) in an amount constituting up to about 25%,by weight, of the total binder, to impart gloss to the labeled product.An example of a preferred vinyl chloride/vinyl acetate resin is VAGH(Union Carbide), a high molecular weight, partially-hydrolyzed vinylchloride/vinyl acetate resin having a composition of approximately 90percent vinyl chloride, 4 percent vinyl acetate, with a hydroxyl contentof approximately 2.3 percent.

[0032] The cross-linking system of the subject ink compositionpreferably comprises (i) a cross-linking resin for cross-linking theresinous binder and (ii) a heat-activatable catalyst for catalyzing thecross-linking of the cross-linker to the resinous binder within about1-2 minutes after transfer of label 21 to an article heated to atemperature in the range of about 250° F.-325° F., preferably about 275°F.-325° F. Examples of suitable cross-linking resins include partiallymethylated melamine-formaldehyde resins of the type present in the CYMEL300 series of partially methylated melamine-formaldehyde resin solutions(Cytec Industries, Inc., West Paterson, N.J.) and, in particular, CYMEL370 partially methylated melamine-formaldehyde resin solution (88±2%nonvolatiles, iBuOH solvent). Such a cross-linker is preferably presentin the ink composition in an amount constituting about 5%-10%, byweight, of the total binder. An example of a suitable catalyst is anamine-blocked sulfonic acid catalyst, such as Nacure® 1323 blockedcatalyst (King Industries, Norwalk, Conn.). Such a catalyst ispreferably present in the ink composition in an amount constitutingabout 0.01% to 1%, by weight, of the total binder.

[0033] The colorant is a pigment and is preferably present in the inkcomposition in an amount representing about 50% to 200%, by weight, ofthe other non-volatile components of the formulation. Where the pigmentis titanium dioxide, the relative proportion of colorant to the othernon-volatile components is preferably about 2:1, by weight,respectively; for pigments other than titanium dioxide, the relativeproportion of colorant to the other non-volatile components ispreferably about 1:2, respectively.

[0034] The one or more volatile solvents are typically volatile solventsof the type commonly used in heat-transfer label inks and may be, forexample, a mixture of methyl ethyl ketone (MEK) and toluene, saidMEK/toluene mixture preferably being a 1:1 mixture and preferably beingpresent in the ink composition in an amount constituting about 40%-75%,by weight, of the total ink composition. The particular proportion ofsolvent(s) to non-volatile components is typically dependent upon theviscosity requirements for printing, with the objective typically beingto maximize the percentage of non-volatiles (and, therefore, viscosity)while still achieving good print quality.

[0035] Illustrative ink formulations for use in making label 21 are asfollows: % By Weight Formulation No. 1 (White) Titanium dioxide 16.67ViTEL ® 2700 copolyester resin 3.75 ViTEL ® 2300 copolyester resin 3.75VAGH vinyl chloride/vinyl acetate resin 0.42 Cymel 370melamine-formaldehyde resin 0.42 Nacure 1323 amine-blocked sulfonic acidcatalyst 0.024 MEK 37.5 Toluene 37.5 Formulation No. 2 (Non-white)Non-white pigment 8.33 ViTEL ® 2700 copolyester resin 7.5 ViTEL ® 2300copolyester resin 7.5 VAGH vinyl chloride/vinyl acetate resin 0.83 Cymel370 melamine-formaldehyde resin 0.83 Nacure 1323 amine-blocked sulfonicacid catalyst 0.047 MEK 37.5 Toluene 37.5

[0036] Assembly 11 is particularly well-suited for use in decoratingglass articles, such as glass containers. (Assembly 11 may also be usedto decorate plastic articles, such as polyethylene napthylene (PEN)articles, or other types of non-glass articles that are capable ofwithstanding the elevated preheating temperatures needed to activate thecross-linking system of label 21.) In use, such glass articles arepreferably treated, prior to labeling, with a silane adhesion promoterof the type described in U.S. Pat. No. 3,907,974, inventor Smith, whichissued Sep. 23, 1975, and which is incorporated herein by reference. Thesilane-treated glass articles are then pre-heated in a conventionalmanner to a temperature of about 250° F.-325° F., preferably about 275°F.-325° F. While at said temperature, the silane-treated glass articlesare then decorated by bring labels 21 into direct contact therewithwhile sufficient heat (about 300 to 450° F.) is applied to the bottom ofcarrier 13 to cause skim coat 19 to soften sufficiently to releaselabels 21 from carrier 13 and to cause the binder in label 21 to becometacky. Within a very short time after transfer of label 21 onto theglass article and without any need for post-heating, label 21 cures dueto the heat-activation of the cross-linking system therewithin.

[0037] The above-described decoration of an article using assembly 11may be performed using conventional heat-transfer machinery (e.g.,conventional cascading unit for applying silane adhesion promoter to theglass article, conventional preheating unit for heating the glassarticle to about 250° F.-325° F., and conventional turret assembly forapplying label to article from web).

[0038] As can readily be appreciated, one advantage of assembly 11, asopposed to conventional heat-transfer label assemblies, is that nopost-heating of the decorated article is necessary since label 21 curessubstantially instantaneously after transfer. Moreover, the decorationof an article with assembly 11 can be performed without requiring anychanges to the pre-decorating and decorating steps conventionallyemployed in heat-transfer labeling. Another advantage is that assembly11 obviates the need for protective lacquer and adhesive layerssurrounding the ink design layer. At the same time, the aestheticquality of label 21 of assembly 11 is comparable to or better thanexisting heat-transfer labels (in part because some existing labelsexperience a problem of hazing in the protective lacquer layer).

[0039] It should be noted that, by omitting the colorant from label 21,one can obtain a fast-curing protective lacquer or adhesive layer thatmay be substituted for a corresponding layer in a conventionalheat-transfer label assembly.

[0040] Referring now to FIG. 2, there is shown a schematic section viewof a second embodiment of a heat-transfer label assembly constructedaccording to the teachings of the present invention, said heat-transferlabel assembly being represented generally by reference numeral 101.

[0041] Assembly 101 is similar in many respects to assembly 11, theprincipal difference between the two assemblies being that assembly 101comprises a carrier 103, instead of carrier 13, and does not comprise askim coat 19. Carrier 103 comprises a polymeric substrate 105 and arelease coating 107 deposited on top of polymeric substrate 105.Substrate 105 is preferably a polymeric film selected from the groupconsisting of polyesters, such as polyethylene terephthalate,polyethylene napthylene; polyolefins, such as polyethylene andpolypropylene; and polyamides.

[0042] More preferably, substrate 105 is a clear plastic film of thetype described above. As can readily be appreciated, one benefit tousing a clear material as substrate 105 is that, if desired, one caninspect the quality of the printed matter of the label by looking atsaid printed matter through substrate 105 (from which perspective saidprinted matter appears as it will on the labeled article), as opposed tolooking at said printed matter through the adhesive layer of the label(from which perspective said printed matter appears as the mirror imageof what will appear on the labeled article).

[0043] A particularly preferred plastic material for use as substrate105 is a clear polyester film, such as a clear polyethyleneterephthalate (PET) film. This is because, at least as compared to someother plastic materials like polyethylene and polypropylene, polyesteris a strong plastic material and makes a good substrate to be printedonto. In addition, unlike polyethylene, polyester does not tend tosoften and become tacky at the types of temperatures typicallyencountered during heat-transfer. Typically, substrate 105 has athickness of about 1-2 mil.

[0044] Coating 107 is preferably applied directly on top of substrate105. Coating 107 is a thermoset release material that separates cleanlyfrom label 21 and is not transferred, to any visually discernibledegree, with label 21 onto an article being labeled. (For purposes ofthe present specification and claims, the term “visually discernible” isto be construed in terms of an unaided or naked human eye.) Preferably,release coating 107 is clear for the same types of reasons given abovein connection with substrate 105.

[0045] Coating 107 does not contain any waxes or any silicones, exceptto the limited extent provided below, and the terms “non-wax” and“non-silicone,” when used in the present specification and claims todescribe and to define the present release layer or coating, are definedherein to exclude from said release layer or coating the presence of anyand all waxes and silicones not encompassed by the limited exceptionsprovided below or described in published PCT Application No. WO01/03950, published Jan. 18, 2001, the disclosure of which isincorporated herein by reference.

[0046] Coating 107 preferably has a thickness of about 0.01 to 10microns, more preferably about 0.02 to 1 micron, even more preferablyabout 0.1 micron. In addition, coating 107 preferably has a totalsurface energy of about 25 to 35 mN/m (preferably about 30 mN/m), ofwhich about 0.1 to 4 mN/m (preferably about 1.3 mN/m) is polar surfaceenergy. Furthermore, when analyzed by XPS (X-ray photoelectronspectroscopy), coating 107 preferably has a carbon content (by atomic %)of about 90 to 99.9% (preferably about 97%) and an oxygen content (byatomic %) of about 0.1 to 10% (preferably about 3%). Accordingly,coating 107 is predominantly a hydrocarbon in its chemical makeup.

[0047] An example of a coated polymer film suitable for use as carrier103 of the present invention is available from DuPont Corp. (Wilmington,Del.) as product number 140AXM 701 (140 gauge coated polyester film).Other coated polymer films which may be used as carrier 103 aredescribed in European Patent Application No. 819,726, published Jan. 21,1998, which document is incorporated herein by reference. Theaforementioned European patent application teaches a coated filmstructure preferably comprising:

[0048] (i) polymers selected from the group consisting of polyesterssuch as polyethylene terephthalate, polyethylene napthylene; polyolefinssuch as polyethylene and polypropylene; and polyamides; wherein saidpolymers form a polymeric film surface; and

[0049] (ii) a primer coating comprising:

[0050] (A) functionalized α-olefin containing copolymers, preferablyacid functionalized α-olefin containing copolymers, selected from thegroup consisting of ethylene/acrylic acid copolymers;ethylene/methacrylic acid copolymers; ethylene/vinylacetate/acrylic acidterpolymers; ethylene/methacrylamide copolymers; ethylene/glycidylmethacrylate copolymers; ethylene/dimethylaminoethyl methacrylatecopolymers; ethylene/2-hydroxyethyl acrylate copolymers;propylene/acrylic acid copolymers; etc. and

[0051] (B) crosslinking agents selected from the group consisting ofamino formaldehyde resins, polyvalent metal salts, isocyanates, blockedisocyanates, epoxy resins and polyfunctional aziridines;

[0052] (iii) wherein said primer coating is applied as a primer to thepolymeric film surface, preferably in its amorphous or semi-orientedstate and reacted with newly generated polymeric film surfaces formedduring uniaxial or biaxial stretching and heat setting.

[0053] Although the above-described polymeric film surface is preferablyformed of a polyester, a polyolefin, or a polyamide, it may be formedform any material capable of being formed into a sheet or film. Thepolymeric film surface should be capable of binding or reacting with anacid-functionalized α-olefin copolymer to form a modified film base.

[0054] The above-mentioned polymer films can be manufactured by anextrusion process, such as a cast film or blown film process. In a castfilm process, the polymer resin is first heated to a molten state andthen extruded through a wide slot die in the form of an amorphous sheet.The sheet-like extrudate is rapidly cooled or “quenched” to form a castsheet of polyester by contacting and traveling partially around apolished, revolving casting drum. Alternatively, the extrudate can beblown in a conventional blown film process. Regardless of the process,however, the polyester sheet is preferably uniaxially or biaxially(preferably biaxially) stretched in the direction of film travel(machine direction) and/or perpendicular to the machine direction(traverse direction), while being heated to a temperature in the rangeof from about 80° C. to 160° C., preferably about 90° C. to 110° C., thedegree of stretching may range from 3.0 to 5.0 times the original castsheet unit dimension, preferably from about 3.2 to about 4.2 times theoriginal cast sheet dimension. Reaction with the newly generated polymerfilm surfaces formed during stretching preferably occurs at temperaturesabout 130° C. or higher.

[0055] Additives such as coating aids, wetting aids such as surfactants(including silicone surfactants), slip additives, antistatic agents canbe incorporated into the primer coating in levels from 0 to 50% based onthe total weight of additive-free coating solids.

[0056] In another embodiment (not shown), a paper substrate, such aspaper substrate 15, is applied to the bottom of carrier 103.

[0057] The embodiments of the present invention recited herein areintended to be merely exemplary and those skilled in the art will beable to make numerous variations and modifications to it withoutdeparting from the spirit of the present invention. For example, itshould be appreciated that one may add, either directly or throughtrans-layer migration, trace or non-functional minor amounts of waxes orsilicones to the release layer described herein as “non-wax” and“non-silicone” without being outside the scope of applicants' invention.Thus, the terms “non-wax” and “non-silicone” as used herein is intendedto embrace this possibility. All such variations and modifications areintended to be within the scope of the present invention as defined bythe claims appended hereto.

What is claimed is:
 1. A heat-transfer label assembly, saidheat-transfer label assembly comprising: (a) a carrier; (b) a wax skimcoat deposited onto said carrier; and (c) a heat-transfer label, saidheat-transfer label being deposited onto said wax skim coat for transferof said heat-transfer label from said carrier to an article underconditions of heat and pressure, said heat-transfer label comprising oneor more ink design layers, each of said ink design layers beingthermosetting within about 1-2 minutes after said ink design layer hasbeen transferred to an article heated to a temperature of about 250°F.-325° F.
 2. The heat-transfer label assembly as claimed in claim 1wherein said heat-transfer label consists of said one or more ink designlayers.
 3. The heat-transfer label assembly as claimed in claim 1wherein each of said ink design layers comprises a binder, a colorantand a cross-linking system, said cross-linking system being adapted toeffect cross-linking of the binder within about 1-2 minutes after saidink design layer has been transferred to an article heated to atemperature of about 250° F.-325° F.
 4. The heat-transfer label assemblyas claimed in claim 3 wherein said binder comprises one or more resinsselected from the group consisting of polyester resins, polyester/vinylresins, polyamide resins, phenoxy resins, epoxy resins, polyketoneresins, and acrylic resins.
 5. The heat-transfer label assembly asclaimed in claim 4 wherein said binder additionally comprises a vinylchloride/vinyl acetate resin.
 6. The heat-transfer label assembly asclaimed in claim 5 wherein said vinyl chloride/vinyl acetate resinconstitutes up to about 25%, by weight, of said binder.
 7. Theheat-transfer label as claimed in claim 4 wherein said binder comprisesa copolyester resin having a high tensile strength and low elongation.8. The heat-transfer label as claimed in claim 3 wherein said colorantis a pigment, said pigment being present in an amount ranging from about50% to about 200%, by weight, of the total of said binder and saidcross-linking system.
 9. The heat-transfer label as claimed in claim 8wherein said pigment is titanium dioxide.
 10. The heat-transfer label asclaimed in claim 3 wherein said cross-linking system comprises (i) across-linking resin for cross-linking said binder and (ii) aheat-activatable catalyst for catalyzing the cross-linking of saidcross-linking resin to the binder within about 1-2 minutes aftertransfer of said heat-transfer label to an article heated to atemperature in the range of about 250° F.-325° F.
 11. The heat-transferlabel as claimed in claim 10 wherein said cross-linking resin is presentin an amount constituting about 5%-10%, by weight, of said binder. 12.The heat-transfer label as claimed in claim 10 wherein saidcross-linking resin comprises a melamine-formaldehyde resin.
 13. Theheat-transfer label as claimed in claim 12 wherein said cross-linkingresin comprises a partially methylated melamine-formaldehyde resin. 14.The heat-transfer label as claimed in claim 12 wherein saidheat-activatable catalyst is an amine-blocked sulfonic acid catalyst.15. The heat-transfer label assembly as claimed in claim 1 wherein saidcarrier comprises a paper substrate overcoated with a layer ofpolyethylene, said wax skim coat being deposited onto said polyethylenelayer.
 16. A heat-transfer label assembly, said heat-transfer labelassembly comprising: (a) a carrier; and (b) a heat-transfer label, saidheat-transfer label being deposited onto said carrier for transfer ofsaid heat-transfer label from said carrier to an article underconditions of heat and pressure, said heat-transfer label comprising oneor more ink design layers, each of said ink design layers beingthermosetting within about 1-2 minutes after said ink design layer hasbeen transferred to an article heated to a temperature of about 250°F.-325° F.; (c) wherein said carrier is made of a non-wax material thatseparates cleanly from said heat-transfer label with no visuallydiscernible portion of said carrier being transferred to the articlealong with said heat-transfer label.
 17. The heat-transfer labelassembly as claimed in claim 16 wherein said carrier comprises apolymeric film overcoated with a release coating made of a non-wax,non-silicone, thermoset release material, said release coating having atotal surface energy of about 25 to 35 mN/m, of which about 0.1 to 4mN/m is polar surface energy, and having a carbon content (by atomic %)of about 97% and an oxygen content (by atomic %) of about 3%, asmeasured by X-ray photoelectron spectroscopy.
 18. The heat-transferlabel assembly as claimed in claim 17 wherein said polymeric film ismade of a polymer selected from the group consisting of polyesters,polyolefins and polyamides and wherein said release coating is made by(i) applying to the polymeric film in its amorphous or semi-orientedstate a composition comprising (a) a functionalized α-olefin containingcopolymer and (b) a crosslinking agent; and (ii) reacting saidcomposition with the carrier during uniaxial or biaxial stretching andheat setting.
 19. The heat-transfer label assembly as claimed in claim16 wherein said heat-transfer label consists of said one or more inkdesign layers.
 20. The heat-transfer label assembly as claimed in claim16 wherein each of said ink design layers comprises a binder, a colorantand a cross-linking system, said cross-linking system being adapted toeffect cross-linking of the binder within about 1-2 minutes after saidink design layer has been transferred to an article heated to atemperature of about 250° F.-325° F.
 21. The heat-transfer labelassembly as claimed in claim 20 wherein said binder comprises one ormore resins selected from the group consisting of polyester resins,polyester/vinyl resins, polyamide resins, phenoxy resins, epoxy resins,polyketone resins, and acrylic resins.
 22. The heat-transfer labelassembly as claimed in claim 21 wherein said binder additionallycomprises a vinyl chloride/vinyl acetate resin.
 23. The heat-transferlabel assembly as claimed in claim 22 wherein said vinyl chloride/vinylacetate resin constitutes up to about 25%, by weight, of said binder.24. The heat-transfer label as claimed in claim 21 wherein said bindercomprises a copolyester resin having a high tensile strength and lowelongation.
 25. The heat-transfer label as claimed in claim 20 whereinsaid colorant is a pigment, said pigment being present in an amountranging from about 50% to 200%, by weight, of the total of said binderand said cross-linking system.
 26. The heat-transfer label as claimed inclaim 25 wherein said pigment is titanium dioxide.
 27. The heat-transferlabel as claimed in claim 20 wherein said cross-linking system comprises(i) a cross-linking resin for cross-linking said binder and (ii) aheat-activatable catalyst for catalyzing the cross-linking of saidcross-linking resin to the binder within about 1-2 minutes aftertransfer of said heat-transfer label to an article heated to atemperature in the range of about 250° F.-325° F.
 28. The heat-transferlabel as claimed in claim 27 wherein said cross-linking resin is presentin an amount constituting about 5%-10%, by weight, of said binder. 29.The heat-transfer label as claimed in claim 27 wherein saidcross-linking resin comprises a melamine-formaldehyde resin.
 30. Theheat-transfer label as claimed in claim 29 wherein said cross-linkingresin comprises a partially methylated melamine-formaldehyde resin. 31.The heat-transfer label as claimed in claim 29 wherein saidheat-activatable catalyst is an amine-blocked sulfonic acid catalyst.32. An ink formulation comprising: (a) a binder resin; (b) a colorant;(c) one or more volatile solvents; and (d) a cross-linking system, saidcross-linking system being adapted to effect cross-linking of the binderresin within about 1-2 minutes after application of a dried, printeddesign made with said ink formulation to an article heated to atemperature of about 250° F.-325° F.
 33. The ink formulation as claimedin claim 32 wherein said binder resin comprises one or more resinsselected from the group consisting of polyester resins, polyester/vinylresins, polyamide resins, phenoxy resins, epoxy resins, polyketoneresins, and acrylic resins.
 34. The ink formulation as claimed in claim33 wherein said binder resin additionally comprises a vinylchloride/vinyl acetate resin.
 35. The ink formulation as claimed inclaim 34 wherein said vinyl chloride/vinyl acetate resin constitutes upto about 25%, by weight, of said binder resin.
 36. The ink formulationas claimed in claim 33 wherein said binder comprises a copolyester resinhaving a high tensile strength and low elongation.
 37. The inkformulation as claimed in claim 32 wherein said colorant is a pigment,said pigment being present in an amount ranging about 50% to 200%, byweight, of the total of said binder resin and said cross-linking system.38. The ink formulation as claimed in claim 37 wherein said pigment istitanium dioxide.
 39. The ink formulation as claimed in claim 32 whereinsaid cross-linking system comprises (i) a cross-linking resin forcross-linking said binder and (ii) a heat-activatable catalyst forcatalyzing the cross-linking of said cross-linking resin to the binderresin within about 1-2 minutes after application of a dried, printeddesign made with said ink formulation to an article heated to atemperature in the range of about 250° F.-325° F.
 40. The inkformulation as claimed in claim 39 wherein said cross-linking resin ispresent in an amount constituting about 5%-10%, by weight, of saidbinder resin.
 41. The ink formulation as claimed in claim 39 whereinsaid cross-linking resin comprises a melamine-formaldehyde resin. 42.The ink formulation as claimed in claim 41 wherein said cross-linkingresin comprises a partially methylated melamine-formaldehyde resin. 43.The ink formulation as claimed in claim 41 wherein said heat-activatablecatalyst is an amine-blocked sulfonic acid catalyst.
 44. A method ofdecorating a glass article, said method comprising the steps of: (a)providing a heat-transfer label assembly, said heat-transfer labelassembly comprising: (i) a carrier; and (ii) a heat-transfer label, saidheat-transfer label being releasably secured to said carrier fortransfer of said heat-transfer label from said carrier to a glassarticle under conditions of heat and pressure, said heat-transfer labelcomprising one or more ink design layers, each of said ink design layersbeing thermosetting within about 1-2 minutes after said ink design layerhas been transferred to a glass article heated to a temperature of about250° F.-325° F.; (b) providing a glass article; (c) heating said glassarticle to a temperature of about 250° F.-325° F.; and (d) while saidglass article is at said temperature of about 250° F.-325° F.,transferring said heat-transfer label from said carrier to said glassarticle.
 45. The method as claimed in claim 44 wherein saidheat-transfer label consists of said one or more ink design layers. 46.The method as claimed in claim 45 wherein said carrier comprises a papersubstrate overcoated with a layer of polyethylene and wherein saidheat-transfer label assembly further comprises a wax skim coat depositedon said layer of polyethylene, said heat-transfer label being depositedon said wax skim coat.
 47. The method as claimed in claim 45 whereinsaid carrier comprises wherein said carrier comprises a polymeric filmovercoated with a release coating made of a non-wax, non-silicone,thermoset release material, said release coating having a total surfaceenergy of about 25 to 35 mN/m, of which about 0.1 to 4 mN/m is polarsurface energy, and having a carbon content (by atomic %) of about 97%and an oxygen content (by atomic %) of about 3%, as measured by X-rayphotoelectron spectroscopy.
 48. The method as claimed in claim 47wherein said polymeric film is made of a polymer selected from the groupconsisting of polyesters, polyolefins and polyamides and wherein saidrelease coating is made by (i) applying to the polymeric film in itsamorphous or semi-oriented state a composition comprising (a) afunctionalized α-olefin containing copolymer and (b) a crosslinkingagent; and (ii) reacting said composition with the carrier duringuniaxial or biaxial stretching and heat setting.
 49. The method asclaimed in claim 44 wherein each of said ink design layers comprises abinder, a colorant and a cross-linking system, said cross-linking systembeing adapted to effect cross-linking of the binder within about 1-2minutes after said ink design layer has been transferred to a glassarticle heated to a temperature of about 250° F.-325° F.
 50. The methodas claimed in claim 49 wherein said binder comprises one or more resinsselected from the group consisting of polyester resins, polyester/vinylresins, polyamide resins, phenoxy resins, epoxy resins, polyketoneresins, and acrylic resins.
 51. The method as claimed in claim 50wherein said binder additionally comprises a vinyl chloride/vinylacetate resin.
 52. The method as claimed in claim 50 wherein said bindercomprises a copolyester resin having a high tensile strength and lowelongation.
 53. The method as claimed in claim 49 wherein said colorantis a pigment, said pigment being present in an amount ranging from about50% to 200%, by weight, of the total of said binder and saidcross-linking system.
 54. The method as claimed in claim 49 wherein saidcross-linking system comprises (i) a cross-linking resin forcross-linking said binder and (ii) a heat-activatable catalyst forcatalyzing the cross-linking of said cross-linking resin to the binderwithin about 1-2 minutes after transfer of said heat-transfer label toan article heated to a temperature in the range of about 250° F.-325° F.55. The method as claimed in claim 54 wherein said cross-linking resincomprises a melamine-formaldehyde resin and wherein saidheat-activatable catalyst is an amine-blocked sulfonic acid catalyst.56. A heat-transfer label assembly, said heat-transfer label assemblycomprising: (a) a carrier; and (b) a heat-transfer label, saidheat-transfer label being releasably secured to said carrier fortransfer of said heat-transfer label from said carrier to an articleunder conditions of heat and pressure, said heat-transfer labelcomprising one or more ink design layers, each of said ink design layersbeing thermosetting within about 1-2 minutes after said ink design layerhas been transferred to an article heated to a temperature of about 250°F.-325° F.
 57. The heat-transfer label assembly as claimed in claim 56wherein said heat-transfer label consists of said one or more ink designlayers.